应用于 KeyValuePair的DebuggerTypeProxyAttribute示例仅显示 Value 成员:
using System.Collections.Generic;
using System.Diagnostics;
[assembly: DebuggerTypeProxy(typeof(ConsoleApp2.KeyValuePairDebuggerTypeProxy<,>), Target = typeof(KeyValuePair<,>))]
// alternative format [assembly: DebuggerTypeProxy(typeof(ConsoleApp2.KeyValuePairDebuggerTypeProxy<,>), TargetTypeName = "System.Collections.Generic.KeyValuePair`2")]
namespace ConsoleApp2
{
    class KeyValuePairDebuggerTypeProxy<TKey, TValue>
    {
        private KeyValuePair<TKey, TValue> _keyValuePair; // beeing non-public this member is hidden
        //public TKey Key => _keyValuePair.Key;
        public TValue Value => _keyValuePair.Value;
        public KeyValuePairDebuggerTypeProxy(KeyValuePair<TKey, TValue> keyValuePair)
        {
            _keyValuePair = keyValuePair;
        }
    }
    class Program
    {
        static void Main(string[] args)
        {
            var dictionary = new Dictionary<int, string>() { [1] = "one", [2] = "two" };
            Debugger.Break();
        }
    }
}

在 Visual Studio 2017 上测试